A press machine and a material transfer device forming a transfer press machine are disposed in real space to have a specific relative positional relationship. A material can be pressed while transferring the material during a transfer press cycle in which the press operation of the press machine and the transfer operation of the material transfer device are synchronized.
A press machine which presses a material utilizing the press (slide) operation of a slide is roughly classified as a flywheel energy storage system or a servomotor drive system. A material transfer device which can transfer a material from a pre-placed die (e.g. first die) to a post-placed die (e.g. second die) utilizing the transfer operation of a finger is roughly classified as a mechanical coupling (e.g. crankshaft and transfer power shaft are connected) system or a robot system. Since a mechanical-coupling material transfer device is associated (synchronized) with a press machine by means of mechanical coupling, a press operation (slide moving operation) according to a press (slide) motion and a transfer operation according to a transfer motion do not interfere.
On the other hand, a robot material transfer device is formed so that the material transfer operation starts when the actual crank angle which changes along with the press operation has reached the transfer start angle set in advance. In a flywheel energy storage press machine, the press motion changes in proportion to an increase (decrease) in strokes per minute (SPM). Therefore, it is not difficult to change the setting of the transfer operation pattern of the material transfer device.
On the other hand, when using a servomotor-drive press machine (see JP-A-2003-181698), it is desirable to use a servomotor-drive material transfer device in order to make the most of the universal motion of the press machine. In this case, the material transfer device is also formed so that the material transfer operation starts when the actual crank angle which changes along with the press operation has reached the transfer start angle set in advance.
In a three-dimensional transfer system, a material is transferred (e.g. brought in and out) in a state in which each transfer (e.g. clamp-unclamp, lift-down, and advance-return) operation and slide moving operation are synchronized so that interference does not occur. Specifically, the slide position is detected from an output signal (rotational angle signal) from an encoder provided to a crankshaft to determine the transfer operation pattern of the material transfer device. Therefore, the component (e.g. finger attached to feed bar or material) of the material transfer device and a die (e.g. upper die) of the press machine can be prevented from contacting (interfering) irrespective of the slide position during pressing.
However, it is troublesome and takes time for the operator to optimize the transfer operation pattern of the material transfer device (i.e. transfer motion) for the press motion each time the setting of the press operation pattern (i.e. press (slide) motion) is changed. In order to avoid such complexity, the tendency is to employ an operation in which the press motion is performed at a low speed and the transfer motion is made constant. This makes it impossible to fully utilize the advantage which allows selection of an arbitrary press motion (e.g. decreasing the processing speed in the pressing region or making the processing speed constant or achieving a stop operation at the bottom dead center). Moreover, it is extremely difficult to accurately and promptly set press conditions by intuition or an empirical rule to avoid interference.
The SPM of the press machine is restricted by the limit SPM of the material transfer device. The limit SPM is determined by the mechanical rigidity of each transfer mechanism and the maximum acceleration and the maximum speed determined by the amount of inertia, characteristics of the servomotor, and the like. Therefore, in order to increase the limit SPM, it is necessary to increase the operation angle range (determined by the transfer operation start angle and the transfer operation finish angle). However, the operation angle of the press machine is limited (360 degrees). Specifically, when the operation angle range is made constant, the limit SPM of the material transfer device cannot be increased without reducing the transfer moving amount. On the other hand, when the transfer moving amount is made constant, the limit SPM cannot be increased by increasing the transfer time if the operation angle range is not increased.
In order to deal with this problem, the operation angle range may be increased by causing an unclamp (UCL) operation, a return (RTN) operation, and a clamp (CLP) operation shown in FIG. 27(A) to partially overlap (simultaneous operation), as indicated by the solid line in FIG. 27(B), for example. In the case of a three-dimensional transfer, an unclamp (UCL) operation, a return (RTN) operation, a clamp (CLP) operation, a lift (LFT) operation, an advance (ADV) operation, and a down (DWN) operation shown in FIG. 28(A) are caused to partially overlap (simultaneous operation), as shown in FIG. 28(B). However, since interference occurs with a significantly high probability when enabling the overlapping operation, it is necessary to more carefully check whether or not interference occurs between the press machine and the material transfer device while operating the press machine at a low speed. In more detail, interference checks between respective parts and operation angle setting operations are repeatedly performed while gradually increasing the press speed to find an appropriate point.
In order to avoid such complexity, an operation tends to be employed in which the press motion is performed at a low speed and the transfer motion is made constant. This makes it impossible to fully utilize the characteristics of the servomotor drive press machine, that is, the advantage which allows selection of an arbitrary press motion (e.g. decreasing the processing speed in the pressing region or making the processing speed constant or achieving a stop operation at the bottom dead center). In this case, it is also extremely difficult to accurately and promptly set press conditions by intuition or an empirical rule to avoid interference.
Therefore, the applicant of the invention has proposed a transfer press machine which can maximize productivity while avoiding interference between the press machine and the material transfer device from the viewpoint of matching optimization of the press motion and the transfer motion (JP-A-2003-245800).
The previously proposed press machine is formed so that adjusted press conditions in which interference between the material transfer device and the die is prevented can be calculated utilizing press (processing) operation information according to input press (processing) conditions and material transfer operation information according to input specified material transfer conditions, and a motor can be controlled to achieve a press (processing) operation according to interference avoidable press conditions calculated instead of the set press conditions.